This application requests support for our continuing research activities in evolutionary theory, and in the analysis of molecular sequence data. The emphasis is on developing mathematical, statistical, and computing concepts and methods to help assess and interpret molecular sequence features and determinants of evolutionary processes. Our research program will concentrate in four main areas. 1) Studies of the evolution of social traits with emphasis on altruistic and cooperative behaviors; 2) studies in evolutionary theory and processes including sex allocation and sex conversion dynamics and the evolution of modifier genes under differential fertility regimes; (3) human population genetics with the development and interpretation of gene frequently maps and modeling of the evolution of traits subject to genetic and cultural influences; (4) studies of molecular sequence data including investigations on the nature of codon and amino acid preferences with respect to different classifications of genes and an extensive analysis of charge and hydropathy configurations over different categories of genes in many species and possible interpretations for function and structure. The interplay between theoretical analysis, data analysis, computer algorithms, and interaction with biologists and medical faculty at Stanford has been a key factor in our program. The unique collaboration between our groups and members of the biology and medical departments provides an ideal framework for achieving the research objectives defined in this grant.